Cotton lint cleaner



April 15, 1958 D. D. DAY

COTTONLINT CLEANER 5 Sheets-Sheet 1 Filed Jan. 11, 1955 Fig. I

INVENTOR Dewey D Day 2 April 15, 1958 D. D. DAY co'r'rou LINT CLEANER 5 Sheets-Sheet 2 Filed Jan. 11, 1955 INVENTOR. Dewey D. Day

April 15, 1958 D. D. DAY

COTTON LINT CLEANER Flled Jan 11. 1955 IIIII nl lillall I I 5 Sheets-Sheet 5 v INVENTOR.

Dewey D. Day- April 15, 1958 D. D DAY 2,830,328 I COTTON LINT CLEANER Filed Jan. 11, 1955 5 Sheets-Sheet-4 Dewey. D. Day BY Q. d wq INVENTORL a April 15, 1958 D. D. DAY 2,830,328

COTTON LINT CLEANER Filed Jan. 11, 1955 Y Sheets-Sheet 5 Fig. I5

INVt'NTOl? Dewey .D. Day

BYW-

United States Patent 2,830,328 I COTTON LINT CLEANER Dewey D. Day, Dallas, Tex assignor to The Murray Company of Texas, Inc., Dallas, Tex., a corporation of Delaware Application January 11, 1955, Serial No. 481,125 16 Claims. (CI. 19-67) This invention pertains to a cotton cleaner designed to be arranged between an individual cotton gin, forming one of a battery of gins, and the battery condenser, such cleaners being employed when the lint cotton is especially dirty, in order to remove a portion of the dirt and trash and thereby to produce an acceptably clean product, before it is delivered to the battery condenser. Some cleaners of this general class, commonly referred to as air flow or line type are so designed that only a relatively small percentage of the lint-carrying air current which brings the lint from the gin to the cleaner is diverted before the lint is delivered to the cleaning means. Thus the major part of the lint-conveying air current must be withdrawn from the trash collecting compartment of the cl aner after the lint has been separated from the air, requiring the provision of a large suction fan for this purpose. In cleaners of that kind, the lint is usually deposited on the toothed periphery of a saw cylinder by the passing air current alone. Since it is not retarded in any Way as it is caught by the moving saw teeth, there is nothing which tends to straighten the fibers or break up lumps or aggregations of fiber, in other'wo'rds, it is not subjected to anything approximating a combing or carding action such as to insure a smooth and; uniformly blended product. a 1- Although it has been proposed to separate substantially all of the air from the lint before delivering the lint to the cleaning instrumentalities and to present the lint to the saw cylinder, after separation from the air, by means of a fluted roller to' which the lint is fed by a plurality of sets of feed rolls, such prior arrangements as are known to me are unduly complicated and fail to provide anything approximating a true combing or carding action.

In accordance with the present invention, the above disadvantages in prior cleaners are substantially overcome, a principal object of the invention being to provide a cleaner wherein substantially all of the air is separated from the lint before the latter is delivered to the cleaning instrumentalities, and having provision for subjecting the lint to a combing or carding action whereby lumps or aggregations of fiber are effectively broken down and the fiber is blended to produce a product of more uniform appearance than has heretofore been obtainable. A further object is to provide cleaning apparatus which is simple in construction and having provision for so embedding the fibers in the teeth of the saw cylinder that a minimum percent of fibers escape during the cleaning operation. A further object is to provide cleaning apparatus such that the amount of air required to be moved and thus the power employed in operating the apparatus is substantially less than in cleaners of the air flow type. A further object is to provide lint cleaning apparatus so designed as to minimize any tendency of the lint to stick to any of the moving parts or to accumulate and cause congestion in the spaces within the apparatus. A further:

object is to-provide cleaner apparatus of this kind where in the fiber is presented to thetoothed saw cylinder by means a rotating rollhaving a toothed peripheral surmovable bearings for said shaft;

face which, in cooperation with the teeth of the saw cylinder, subjects the fibers to a distinct combing or carding operation. Other and further objects and advantages of the invention will be pointed out in the following more detailed description and byreference to the accompanying drawings, wherein. V

Fig. l is a diagrammatic vertical section'illustrating apparatus according to the present invention;

Fig. 2 is a fragmentary vertical section, at substantially the same plane as Fig. 1, but to larger scale, showing details of construction;

Fig. 3 is a fragmentary side elevation, partly in radial section, of a feed roll forming an element of the apparatus;

Fig. 4 is a section on the line 4-4 of Fig. 3, and to larger scale, showing details of the feed roll;

Fig. 5 is an end elevation of a stationary lint-guidebar showing diagrammatically its relation'to the feed roll and the saw cylinder;

Fig. 6 is a fragmentary'longitudinal, diametrical secsection through one of the dofier rolls;

Fig. 7 is a fragmentary section to large scale on the line 7-7 of Fig. 6;

Fig. 8 is a fagmentary transverse section through the screen drum of the condenser section;

Fig. 9 is a fragmentary longitudinal section through the screen drum of the condenser section, and to larger scale than Fig. 8, showing certain'details;

Fig. 10 is a fragmentary detail, to .larger scale than Fig. 1, showing the lint guard and its relation to the saw cylinder; 7

Fig. 11 is a fragmentary longitudinal section through the saw cylinder assembly;

Fig. 12 is a fragmentary vertical section, perpendicular to the shaft of the larger doffer roll, showing one of the Fig. 13 is a fragmentary vertical section through one of the end walls of the casing, showing the means for supporting the movable bearing at one end of the doifer roll shaft;

Fig. '14 is a fragmentary section in a radial plane of the condenser screen drum illustrating in a diagrammatic manner one arrangement of parts for controlling the air fiow through the drum; and

Fig. 15 is a fragmentary section in the same plane as Fig. 14, but to larger scale, showing details of one of the flow controlling valves.

Referring to the drawings, the character C (Fig. 1) designates the cleaner as a whole, this cleaner comprising a casing, usually of sheet metal, having an upper part 10, which may be termed the condenser section, which defines a screen box chamber 11 having an inlet opening at 12 to which is connected the delivery end of a broad fiat duct 13 which leads from the gin stand, not shown. The upper part of the condenser section has a passage 14 for the entering body of lint-carrying air. Within the screen box chamber 11 there is arranged a cylindrical condenser or screen drum 15 mounted on a shaft 16 suitably journaled at its ends in bearings (not shown), supported by the casing. The periphery of the screen drum may be of perforated sheet metal. However, as here illustrated (Figs. 8 and 9), it is of wire cloth K supported by a helix of wire W carried by a rigid frame F mounted on the drum'shaft 16. As diagrammatically illustrated in Fig. 14, the opposite ends of this condenser or screen drum,

which are arranged closely adjacent to the opposite end substantially all of the airwhich, entering through the,

I duct 13, passes inwardly through the openings in the periphery of the condenser or screen drum. Manually ad justable valves V (Figs. 14 and 15) are arranged at the entrances to passages P and may be adjusted to control the effective size of each passage P. By properly adjusting these valves, it is possible to control the effective suction in the duct 13 leading from the gin stand, which is desirable when a battery of lint cleaners is served by the same suction fan.

Below the screen box 11 the casing is shaped to provide a cleaning chamber 17, within which is mounted a saw cylinder 18, and which is carried by a shaft 18*- journaled at its opposite ends in suitable bearings (not shown) supported by the casing. In Fig. 11 a preferred form of saw cylinder is illustrated. This saw cylinder comprises a series of coaxial, peripherally toothed disks or blades 18*, generally similar to those used in gin or linter saws. These blades are splined to the shaft 18, with spacers 18 interposed between them. The spacers are desirably of a thickness to provide a spaced one-fourth inch between adjacent blades. Therendmost blades contact washers 18 and 18 respectively, which are confined between abutment nuts 18 and 18 screw-threaded to the shaft. As shown in Fig. 11, the washers 18 and 18 are of wedge shape and reversely disposed so that the blades 18 lie in inclined, non-radial planes. The angle of inclination is such as compared with the thickness of the spacers 18 that as the saw cylinder rotates the saw teeth move back and forth longitudinally of the cylinder a distance substantially equal to the space :between' adjacent blades. Thus, by reason of this wobbling of the saws, the entire area of the periphery of the cylinder presents teeth to the feed roll, which insures a much better supportfor all of a the lint fibers and results in reduction of lint loss, as compared with a saw cylinder having its blades perpendicular to the shaft. Grid bars are arranged in cooperating relation to the periphery of the saw cylinder, the inner edges of these bars being spaced at short distance from the tips of the teeth of the saw cylinder and operating, as is customary, in apparatus of this type, to knock dirt and trash out of the lint as the latter, carried by the teeth of the saw cylinder, is whipped past the bars. as the cylinder rotates.

The first three of these bars (Fig. 1), indicated at 19, 19" and 19 respectively, are relatively thick, having inner arcuate faces approximately concentric with the saw cylinder, and upper, substantially flat faces which intersect said arcuate faces to form acute edges parallel to the axis ofv the saw cylinder and directed upwardly toward the oncoming saw teeth. As here illustrated, the fiatupper face of each of the bars 19 and 19 is inclined at approximately 40 to a radial plane through the acute edge of said bar. The lower bars 19, 19, 19 and 1'9 are here shown as substantially rectangular. in transverse section and disposed in approximately radial relation to the saw cylinder. The several bars are mounted at'their opposite ends in adjustable brackets 20 carried by theend walls of the casing.

Beneath the condenser or screen drum-15 and between the periphery of the latter and the periphery of the saw cylinder there is arranged an air seal which prevents any substantial part of the air which enters the screen box 11' from passing downwardly into the chamber 17. Preferably there is a slight super-atmospheric pressure in the screen box, although the apparatus will operate at subatmospheric pressure. The air seal, as here illustrated (Figs. 1 and 2), comprises two oppositely rotating dofier rolls 31 and 32 respectively, carried by parallel shafts 33" and 34. The ends of the shaft 33 are journaled in fixed bearings (not shown) carried by, the end walls of the casing;

The rolls 31 and 32 are substantially alike, except that the roll 32 is preferably somewhat larger than the roll 31, for example, the roll 32 may be six inches in outside diameter and the roll 31 five inches in diameter. trated (Fig. 6), each roll'comprises a hollow shell S, of

As illus-' 4 hard rigid material, for instance steel, mounted on flanged hubs H fixed to the roll shaft. Desirably, as illustrated in Fig. 7, each roll has longitudinally extending grooves or flutes 38, which may, for example, be spaced approximately 15 apart circumferentially of the roll and each of a radial depth of the order of As shown in Fig. 7, each flute increases in width outwardly, being for example of the order of Ms in width at its bottom and having its side walls diverging at an angle of approximately 60 to each other. The doffer roll 31 (Fig. 2) is so arranged that its peripheral surface is spaced approximately Vs" from the surface of the condenser drum 15 so that it is operative to scrape off lint which adheres to the surface of the condenser drum, while the peripheral surface of the roll is normally approximately /4' from the surface of the condenser drum.

The bearings B (Figs. 12 and 13) for the shaft 34 are movably supported to slide along horizontal tracks T fixed to the end walls W of the casing, so that the roll 32 may move bodily toward and from the roll 31. Ap-

propriate means, for example springs 37, urge the roll 32 toward the roll 31. Fixed stops limit movement of the shaft bearings in both directions. At their closest approach the surfaces of the rolls 31 and 32 are only a few thousandths of an inch apart, the maximum separation being about one-fourth of an inch. The above minimum spacing is such as to prevent passage of anysubstantial amount of air downwardly between the rolls. As shown in Fig. l, the rolls 31 and 32 are abnormally separated. By appropriate gearing, the rolls are driven in opposite directions at the same surface speed. The springs 37 are a so designed as to produce a pressure of approximately fifty pounds upon the lint passing between the rolls so that the lint in passing between the rolls is firmly gripped at the bite of the rolls.

Each of the rolls 31 and 32 extends substantially from end to end of the casing with conventional means (not shown) for avoiding leakage of air between the ends of the rolls and the end walls of the casing. As above noted, the shafts 33 and 34 are so driven that the doffer rolls turn in opposite directions (as indicated by the arrows, Fig. 2), and at the same linear velocity, the velocity being such that the surface speed of the roll 31 exceeds that of the screen drum 15.

The air seal also comprises a flexible resilient flap 39 fixed at one edge to the part 26 (Fig. 1) and having its opposite margin in wiping contact with roll 31. A similar flexible, resilient flap 40 (Fig. 1) is attached to the lower edge of easing member 10 and has wiping contact with the roll 32 a Below the rolls 31 and 32 and above the saw cylinder 18 there is arranged a feed roll 46. As here illustrated, Figs. 3 and 4, the feed roll 46 comprises a rigid cylindrical core 48, desirably of steel and for example approximately.

three inches; in diameter having screw-threaded axial bores in its opposite ends which receive the screw-threaded end portions or trunnions 47 and 47 respectively. These trunnions turn in bearings (not shown) carried by the casing-one of the trunnions being of sufficient length to receive a driving. element such as a pulley or gear. A strip or ribbon of card clothing is spirally wound about the core 48, being secured to the latter by adhesive, metallic fasteners or both. The card clothing here shown is of the conventional fillet type having inclined teeth 50 formed from wire, for example of approximately 1 mm. in diameter. The axis of the feed roll is so located that the tips of. its teeth are spaced from the surface of doifer roll 31, at the point of nearest approach of the feed and dofier rolls, a distance of the order of A", the vertical distance between the surface of the feed roll and the bite of the clutter rolls being approximately two inches, and so that the teeth of the feed roll pass the teeth of the saw cylinder with a clearance of approximately V This spacing is important in preventing lint from wrapping about the feed roll. As may be observed by reference to Figs. 1 and 2,

the teeth of the feed roll and the teeth of thesaw cylinder point in the same direction as they approach the point of near-tangency of the roll and cylinder.

A rigid guide bar 41 (Figs. 1 and 5) is arranged immediately beneath the doffer roll 31, its ends being fixed in the endwalls of the casing. The upper surface 42 of this bar is spaced approximately 1 from the nearest point on the periphery of theroll 31, and its lower face 43 is horizontal arid in a plane substantially tangent to the roll 46. In the preferred form the right-hand side of the bar 41, as viewed in'Figs. 1 and 5, comprises-two inclined flat faces 44 and 45, the surface 44 being inclined upwardly and to the left at anxangle of approximately 10 to the vertical, while the lower inclined surface 45 is inclined downwardly and to the right at an angle of approximately 40 to the vertical. Below the surface 45 the bar has a vertically narrow face 45* approximately $4 in width.

A horizontal shaft 53 (Figs. 1, 2 andlO) has its axis in a radial plane of the saw cylinder about 16 above the radial plane through the acute edge of the upper grid bar 19. This shaft 53 supports a lint guard G, here shown as comprising a hollow sheet metal shell having a concave inner wall 54 and-anou ter wall 55, with a stiffening rod 56 at its upper edge where the inner and outer walls merge. The upper edge ofthis guard is normally disposed close to the upgoing portion of the peripheral surface of the feed roll 46, while the inner surface of. the wall 54, at its lowest point, is spaced from the tips of the saw teeeth approximately Normally the inner wall 54 of this guard diverges upwardly and away from the saw cylinder. To give access to the saw cylinder at this point the guard is so mounted on the shaft 53 that it may be turned to some such position asis indicated by the broken lines in Fig. 10. The guard .G is operative to prevent lint, which is not firmly caught by the saw'teeth, from escaping. Any lint which is not adequately embedded in the saw teeth and which flies off from the teeth at this point is recaptured by the guard and returned to the 'saw cylinder at the lower edge of the guard. If the guard device G were not used, a considerable amount of lint would be thrown off .from the saw cylinder at the point where the feed roll delivers the lint to the saw cylinder. If the shaft 53 which supports the guard were to be located substantially closer to the top grid bar 19 than above described, the moting action of the top grid bar would be substantially reduced.

Thus the particular location of the guard means, as above described, is important in order to minimize the loss of useful lint, while at the same time to obtain the maximum moting effect. I

The sloping faces of the bar 41 define a passageor'slot 52 (Fig. 5) whose, upper or entrance end is wider than its lower portion, the lower end of this passage being very close to the periphery of the saw cylinder 18 and within the dihedral angle formed by the peripheries of the feed roll 46 and the saw cylinder 18. As may be noted from inspection of Fig. 2, the axis of the toothed feed roll 46 is so located (the shaft of the roll turning in fixed bearings as above pointed out) that the lower portion of the passage 52 is of a width approximately equal to'the distance between the peripheries of the dofier roll 31 and the toothed feed roll 46 at their nearest point of approach. The delivery portion of the passage 52 is sodirected that lint carried downwardly through this passage 52 on the teeth of the feed roll 46 will be moving in substantially the same direction as the periphery of thesaw-cylinder when the lint first comes into contact withthe saw, so that its direction of motion is not substantially changed it being noted that the teeth of the feed roll are moving in the same direction as those of the saw cylinder at this point. r t e At the rear of the saw cylinder there is arranged a rotating doffer brush 22 mounted on a shaft 23, the brush turning oppositely to the saw cylinder and having a peripheral surface velocity exceeding that of the saw cylinder, for example a surface velocity of 7000 feet per 6 Y minute. Running at this'velocity the brushacts as a fan, generating an air current sufficient to carry the lint through the conduit 30- to a battery condenser. The brush is so arranged that its bristles reach substantially to the roots of the teeth of the saw cylinder. This brush is housed in a chamber 24 defined at its top by an upper wall 25 which is spaced from the lower wall 26 of the passage 12 to provide a channel 27 through which atmospheric air may flow toward the periphery of the saw cylinder, the wall 25 terminating at 25 a short distance, for example 1%" from the periphery of the saw cylinder and being spaced from the periphery of the brush 22 to provide a delivery passage 28 leading to the outlet 29 from which the conduit 30 leads to the battery condenser (not shown). The lower wall 20 of the brush chamber 24 is approximately concentric with the brush, being united at its forward end at 20 to the rear wall 56tof the chamber 17 and at its opposite edge to the outer wall of the casing. Between the points 25 and 20 the saw cylinder is exposed to the brush, so that the lint carried by the teeth of the saw cylinder may be doffed by the brush, the lint being swept away from the saw cylinder by the air current generated by the brush and delivered to the outlet 29.

The lower part of the casing of the cleaner is of hopper shape (Fig. 1) comprising the downwardly convergent walls and 56 which lead to a channel having a floor formed by the upper run 57 of an endless belt which receives the dirt and trash which drops between the bars 19, 19 etc. and carries it out through an opening (not shown) in the end wall of the casing, the same belt, if desired, extending along the entire battery of cleaners so as to receive refuse from each in turn. For good results, as an example of the relative sizes of certain of the parts, the diameter of the saw cylinder may be twelve inches; the diameter of doffer roll 31 may be five inches; the

diameter of doffer roll 32 may be six inches; and the diameter of the feed roll 46 may be three inches.

Desirable results have been obtained with the saw cylinder 18 running at a surface speed of 2200 feet per minute; with the brush cylinder 22 running at a surface speed of 7210 feet per minute; with the lint feed roller 46 running at a surface speed of 240 feet per minute;.with both do fier rolls 31 and 32 running at a surface speed of 171 feet per minute; and with the condenser drum running at a surface speed of 120 feet per minute.

The shafts above described which carry the several rotating parts extend to the outside of the casing where they are provided with pulleys, gears or equivalent means (not shown) for the reception and delivery of driving power. I

in the operation of this apparatus, the lint-bearing air current coming from the gin through the duct 13 enters the space 14 above the condenser or screen drum 15, and as the latter rotates in the direction of the arrow (Fig. 1) the lint tends to deposit on the surface of thedrum, while the air moves inwardly through the interstices of the drum and is drawn away through the duct D. The lint either falls off of the surface of the drum 15 in passing downwardly through the screen box 11, or is scraped off of the drum by the edges of the flutes of the roll 31, whose peripheral speed exceeds that of the condenser drum, the lint being compressed between the dofi'er rolls v 31 and 32 to form a patchy bat in which the thickness and the distribution ofthick and thin areas may vary from point to point, transversely of the machine, depending upon the way in which the lint is deposited upon the surface of the drum cylinder 15. As above suggested, the surface of the feed roll 46 moves at a speed for example, of the order of ,4, of that of the saw cylinder. As the lint either falls off of the surface of the drum '15 in passing downwardly through the screen box 11 or is scraped off of the drum by the edges of the flutes of the roll 31, whose peripheral speed exceeds that of the condenser drutn, the lint, moving downwardly and em g ng from between the dotfer rolls 31 and 32 into, the space 45 (Fig. 2), advances until his caught by the teeth of the faster moving feed roll 46 by whichit is pulled down into'the passage 52. As the lint, adhering to, thecard clothing of the feed roll 46 is carried down to a point which is in the vertical plane of the axis of the feed roll, beyond the end of the passage 52, the faster moving teeth of the saw cylinder catch and drag from their embedment in the'card clothing such of the fibers as the saw teeth can accommodate, with excess lint, if any, pressed by the saw teeth back into thecard clothing so as to be carried around' by the feed roll for subsequent presentment in position tobe caught and dragged off by thesaw cylinder. By this action there'is provided a verypronounced carding action with the result that dirt and trashare thoroughly loosened, any lumps of fiber are broken up, and lint fibers are so removed from the feed roll as to blend and smooth the material to assure a very unusual uniformity of cotton.

The bar 41, whose surfaces 44 and 45 define'the fixed left-hand wall of the passagetFig. 4) constitutes a guard, preventing loose lint, not firmly embedded in the teeth of the card-clothing of feed roll 46, from being ejected by centrifugal force, thus insuring that all lint which enters the passage 52 will be caught ultimately by the teeth of the saw cylinder without the possibility of its delivery in uncleaned condition into the passage 28 directly above the doffing brush 22.

As the lint, carried in the; grip of the teeth of the feed roll 46 reaches the end of the passage it is caught by the l teeth of the saw cylinder. The speed of the saw cylinder is such as to create a slight vacuum at the lower end of the passage v52 which helps to pull thelint out of the passage and to embed it in the saw teeth., Since the: roll 46 is moving so much slower than the saw cylinder, the con tact of the lint with the teeth of the saw cylinder tends to drag the lint forwardly, while the teeth of the feed roll are still embedded in the lint, thus providing a very pronounced carding action, with the result that dirt and trash are thoroughly loosened; any lumps are broken up and adjacent lint fibers are so pulled from the feed roll as to blend and smooth out the material-and thus assure a very unusual uniformity of product.

The above described relationship between the. lint feed roll, the guide bar, the condenser, the doffing rolls is apparently necessary to prevent wrapping or accumulation of lint on the feed roll. 7

As the lint is taken by the teeth of the sawcylinder, it is carried about by the latter and past the grid bars where the dirt and trash is separated from the lint and drops down onto the conveyor belt 57, while the clean lint is dotted, from the saw teeth by the brush 22 and delivered to the battery condenser.

Since very little air enters the chamber 17, it is possible to employ the belt conveyor 57 to remove the trash rather than suction means of any sort, so that the necessity for providing pneumatic trash conveying means is avoided.

While one desirable embodiment of the invention has herewith been disclosed by way of example, it is to be understood that the invention is broadly inclusive of any and all modifications falling within the scope of the appended claims.

I claim:

1. In a cotton lint cleaner of the kind in which lint is conveyed from a gin by an air current and which comprises a casing having therein means for separating r "-8 the major portion of the air from the lint, and cleaning instrumentalities including a rotary saw cylinder and spaced parallel grid bars arranged about an arc of the peripheral surface of the cylinder, in combination, a toothed feed roll whose axis is parallelto and fixed relatively to' that of the saw cylinder, the tips of the teeth of the feed roll being closely adjacent to and moving in substantially the same direction as but spaced from the tips of the'teeth of the saw cylinder at the nearest point or approach of the peripheries of the feed roll and saw cylinder, and means turning the toothed feed roll' and the saw cylinder in opposite directions with the peripheral speed of the saw cylinder exceeding that of the toothed cylinder whereby the teeth of the saw cylinder comb the lint while pulling it from the teeth of the feed roll, and means whereby the lint is guided to move in substantially the same direction as the saw teeth as the lint approaches but before it is engaged by said teeth.

2. A cotton lint'cleaner according to claim 1, wherein the clearance between the tips of the teeth of the toothed feed roll and the tips of the saw teeth, at their point of nearest approach, is approximately 5 I 3. A cotton lint cleaner according to claim 1, comprising means for turning the saw cylinder at a peripheral speed of the order of nine times that of the toothed feed roll.

4. A cotton lint cleaner according to claim 1, comprising a rigid guide member extending from end to end of the toothed feed roll and spaced a fixed distance from the peripheral surface of the latter thereby to define a lint passage of constant dimensions, the delivery end of said passage being'adjacent to the periphery of the saw cylinder, the guide member being so shaped and located, relatively to the toothed feed roll that lint, carried downwardly through the passage by the teeth of the feed roll, when approaching the delivery end of the passage is moving in substantially the same direction as the tips of the teeth of the saw cylinder as said tips cross the delivery end of the passage.

5. A cotton lint cleaner according to claim 1, having a fixed guide bar extending from end to end of the feed roll and parallel to the latter, the guide bar having sloping faces spaced from the periphery of the feed roll and arranged to define. a lint passage, the delivery end of the passage being within the angle defined by the approaching and oppositely moving portions of the peripheries of the'feed roll and saw cylinder.

6. A cotton lint cleaner according to claim 1, having a fixed guide bar extending from end to end of and parallel to the feed roll, the guide bar being so located that the teeth of the saw cylinder pass below the guide bar in approaching the feed roll.

7. A cotton lint cleaner according to claim 1, wherein the feed roll has a cylindrical core and the toothed peripheral surface of the feed roll consists of a strip of card clothing wound helically about the core.

8. Acotton lint cleaner of the kind which comprises a rotary'saw cylinder having inclined teeth, a plurality of spaced grid bars arranged about an arc of the peripheral surface of the saw cylinder, a feed roll having inclined teeth and whose axis is parallel to that of the cylinder, the feed roll being so locat ed that the tips of its teeth are closely adjacent to but spaced from the tips of the saw cylinder at the. point of near-tangency of the feed roll and cylinder, means for turning the saw cylind'er oppositely to the toothed feed roll and at a peripheral speed exceeding that of the feed roll, the parts being so constructedand arranged that the tips of the teeth of the saw cylinder'and feed roll are moving in substantially the same direction at the point of near-tangency of the cylinder and roll, and means for directing lint cotton into the angle defined by the approaching portions of the peripheries. of the toothed feed roll and the saw cylinder. 9. A cotton lint cleaner according to claim 8, com- I 9 prising guard means operative to prevent the lint from escaping from the teeth of the saw cylinder at a point intermediate the toothed roll and the first of said grid bars, said' guard means having a concave inner surfacev whichlnormall'y diverges upwardly and away from the periphery of the saw cylinder.

' 10. A cotton lint cleaner according to claim 9, wherein the guard means comprises a member extending longitudinally of the saw cylinder and about the periphery of the saw cylinder from a point adjacent to the upgoing portion of the surface of the toothed feed roll to a point located approximately 16 of arc from the upper edge of the uppermost grid bar.

11. A cotton lint cleaner of the kind which comprises a rotary saw cylinder, a'plurality of spaced grid bars arranged about an arc of the peripheral surface of the saw cylinder, a toothed feed roll having its axis parallel to that of the saw cylinder and so located that the tips of the teeth of the toothed roll are closely adjacent to but spaced from the tips of the teeth of the saw cylinder, means for turning the saw cylinder at a peripheral speed exceeding that of the toothed roll and in the opposite direction, means for directing lint cotton into the angle defined by the approaching peripheries of the toothed roll and saw cylinder, guard means operative to prevent the lint from escaping from the teeth of the saw cylinder at a point intermediate the toothed roll and the first of said grid bars, the guard means comprising a member which extends longitudinally of the saw cylinder and about the periphery of the saw cylinder from a point near the upgoing surface of the feed roll to a point located approximately 16 of arc from the upper edge of the uppermost grid bar, that surface of the guard member which is opposed to the saw cylinder being concave and gradually approaching the saw cylinder in the downward direction, the lower edge of the guard member being spaced from the periphery of the saw cylinder a distance of the order of A 12. In a cotton lint cleaner of the kind which comprises a casing having therein an air seal which divides it into upper and lower chambers respectively, a rotating screen drum within the upper chamber, the interior of said drum communicating with a space wherein subatmospheric pressure is maintained, means for delivering a lint-laden air current into the upper chamber, and cleaning instrumentalities in the lower chamber, said cleaning instrumentalities comprising a combing element having a surface to which lint tends to adhere, a rotary saw cylinder and cooperating grid bars, the air seal which separates the upper and lower chambers comprising a pair of dotfer rolls whose axes are parallel and which turn oppositely at the same surface speed, a fixed member defining one wall of a lint-guiding passage, the lintengaging surface of the combing element forming the opposite wall of said lint-guiding passage, the fixed memher and the combing element being so constructed and arranged that the lint-guiding passage is of predetermined fixed shape and dimensions and tapers downwardly in width and terminates closely adjacent to the periphery of the saw cylinder, the terminal end of said lint-guiding passage being of a width approximating the shortest distance between the lint-engaging surface of the combing element and the peripheral surface of that one of the dotfer rolls which is the nearer to the combing element, the doffer rolls being so located and arranged as to receive lint directly from the screen drum and to deliver it directly to that part ofthe combing element which is moving toward the wider upper end of the said lintguiding passage 13. In a cotton lint cleaner of the kind which comprises a casing having therein an air seal which divides it into upper and lower chambers, respectively, a rotating screen drum within the upper chamber, the interior of said drum communicating with a space wherein subatmospheric pressure is maintained, means for delivering a lint-laden air current into the upper chamber, and cleaninginstrumentalities in the lower chamber, said cleaning instrumentalities comprising a movable combing element, a rotary saw cylinder and cooperating grid bars, the air seal which separates the upper and lower chambers comprising a pair of 'doifer rolls whose axes are parallel and which turn oppositely at the same surface speed, said dofier rolls being arranged to receive lint directly from the screen drum and to deliver it in position to be seized by the movable combing element in the lower chamber, the movable combingelement being a roll' covered with card clothing, said roll turning oppositely to the saw cylinder and being operative to claw into the lint which drops from between the dofier rolls and to move the lint toward the saw cylinder.

14. In a cotton lint cleaner of the kind which comprises a casing having therein an air seal which divides it into upper and lower chambers, respectively, a rotating screen drum within the upper chamber, the interior of said drum communicating with a space wherein subatmospheric pressure is maintained, means for delivering a lint-laden air current into the upper chamber, and cleaning instrumentalities in the lower chamber, said cleaning instrumentalities comprising a movable combing element, a rotary saw cylinder and cooperating grid bars, the air seal which separates the upper and lower chambers comprising a pair of dotfer rolls whose axes are parallel and which turn oppositely at the same surface speed, said doifer rolls being arranged to receive lint directly from the screen drum and to deliver it in position to be seized by the movable combing element in the lower chamber, the movable combing element being a rotary toothed roll whose peripheral speed is greater than that of the doifer rolls and less than that of the saw cylinder, said toothed roll turning oppositely to the saw cylinder, the periphery of the toothed roll being spaced from the periphery of the saw cylinder a distance of approximately M of an inch and from the bite of the dolfer rolls a distance of the order of 2 inches.

15. In a cotton lint cleaner of the kind which comprises a casing having therein an air seal which divides it into upper and lower chambers, respectively, a rotating screen drum within the upper chamber, the interior of said drum communicating with a space wherein sub-atmospheric pressure is maintained, means for delivering a lint-laden air current into the upper chamber, and cleaning instrumentalities in the lower chamber, said cleaning instrumentalities comprising a movable combing element, a rotary saw cylinder and cooperating grid bars, the air seal which separates the upper and lower chambers comprising a pair of doffer rolls Whose axes are parallel and which turn oppositely at the same surface speed, said doifer rolls being arranged to receive lint directly from the screen drum, said dofier rolls being located adjacent to said combing element so as to directly feed lint thereto, both doifer rolls being of rigid material having cylindrical peripheral surfaces provided with longitudinally extending flutes approximately $3 of an inch in depth and a spaced apart approximately 15 and each of a Width of the order of A; of an inch.

16. In a cotton lint cleaner of the kind which comprises a casing having therein an air seal which divides it into upper and lower chambers, respectively, a rotating screen drum within the upper chamber, the interior of said drum communicating with a space wherein sub-atmospheric pressure is maintained, means for delivering a lint-laden air current into the upper chamber, and cleaning instrumentalities in the lower chamber, said cleaning instrumentalities comprising a movable combing element, a rotary saw cylinder and cooperating grid bars, the air seal which separates the upper and lower chambers comprising a pair of doffer rolls Whose axes are parallel and which turn oppositely at the same surface speed, said doffer rolls being arranged to receive lint directly from the screen drum, said doifer rolls being located adjacent 11 a to saidcombing, element so as todirectly feed lint thereto; theoppositelyyturning dofier rollswhichsonstitute theair seal being cylindrical and rigid,;,on'e ,of \saidrolls having a, shaftwhich is mounted in movablebearings whereby said latter roll may bewmoyedhodily toward or, away 5 fromjthe other doffer ,roll, and means yieldingly urging the bodily movabie doffer roll toward theother of said d flFer rolls, the periphery of thatdolferroll, whoses haft is mounted in fixed bearings, being-spaced from the periphery of the screen cylinder a distance of the prder 10 of A of an inch at their points of nearest approach.

; References Cited in the file ofthis patent UNITED STATES PATENTS Moss Mar. 29, 195; 

